Unloader valve

ABSTRACT

A valve housing has opposed inlet and outlet ports connected by a straight through first passageway. A one-way check valve is mounted in the passageway adjacent the outlet port. A bypass port communicates with the first passageway by means of a second passageway having an inner end providing a valve seat for a bypass valve element in the first passageway. The bypass valve element is connected to a piston movable in a cylindrical chamber in the housing and dividing the chamber into a pressure chamber portion and an outer chamber portion, the outer chamber portion communicating with the exterior of the housing. The piston and bypass valve element are yieldingly urged toward valve closing engagement of the bypass valve element with the valve seat by spring means in the outer chamber portion, the housing further defining a third passageway extending from the first passageway adjacent the outlet port to the pressure chamber portion.

SUMMARY OF THE INVENTION

The improved unloader valve of this invention involves housing meanshaving aligned inlet and outlet ports and defining a straight throughfirst passageway connecting the inlet and outlet ports. A one-way checkvalve is disposed in the passageway adjacent the outlet port. Thehousing means further defines a bypass port, a second passagewayconnecting the bypass port with the first passageway, a valve seat atone end of the second passageway and at one side of the firstpassageway, and a cylindrical chamber axially aligned with the valveseat. A piston in the cylindrical chamber divides the chamber into aninner pressure chamber portion and an outer chamber portion open to theexterior of the body means. The body means further defines an openingbetween the pressure chamber portion and the first passageway, and athird passageway communicating at one end with the first passagewaybetween the outlet port and said check valve and at its other end withthe pressure chamber portion. A bypass valve element is disposed in thefirst passageway and has a stem extending through the opening andconnected to said piston, the bypass valve element being movable withthe piston toward and away from valve closing engagement with the valveseat. Yielding means in the outer chamber portion yieldingly urges thepiston and bypass valve element in a valve closing direction.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view in longitudinal section of the unloader valve of thisinvention;

FIG. 2 is a fragmentary view in top plan, as seen from the line 2--2 ofFIG. 1;

FIG. 3 is a fragmentary section taken on the irregular line 3--3 of FIG.1; and

FIG. 4 is a fragmentary section taken on the line 4--4 of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The unloader valve of this invention involves housing means indicatedgenerally at 1, including a generally cruciform housing member 2 havingopposed arms 3 and 4 and other opposed arms 5 and 6 disposed generallynormal to the arms 3 and 4; a tubular housing element 7 screw threadedinto the arm 6; a flanged bushing 8; an annular member 9; and an annularnut 10 screw threaded into the outer end portion of the tubular housingelement 7.

The arms 3 and 4 are hollow and are internally threaded to definerespective inlet and outlet ports 11 and 12 that are connected by astraight-through fluid passageway 13. The passageway 13 is formed toprovide a valve seat 14 for a sealing ring-equipped one way check valve15 having an axially projecting stem 16 that slidably extends through anaxial opening in a bearing member 17 screw-threadedly received in theoutlet port 12. The bearing member 17 is provided with a plurality ofcircumferentially spaced openings 18 for passage of fluid therethrough.A coil compression spring 19 is interposed between bearing member 17 andcheck valve 15 to yieldingly urge the valve 15 toward seating engagementwith the valve seat 14.

The arm 5 defines a screw threaded bypass port 20 that communicates withthe fluid passageway 13 by means of a second passageway 21 that extendsthrough the housing member 2 and annular memeber 9 in a direction normalto the passageway 13. The annular member 9 provides a valve seat for abypass valve element 22 having an elongated stem 23 that is axiallyslidably mounted in the bushing 8. The valve element 22 and its stem 23are axially aligned with the passageway 21, as shown in FIG. 1.

The tubular housing element 7, bushing 8 and annular nut 10 cooperate todefine a cylindrical chamber 24 that is axially aligned with the secondpassageway 21, and which has axially slidably mounted therein a piston25 which divides the chamber 24 into an axially inner pressure chamberportion 26 and an outer chamber portion 27 that communicates with theexterior of the housing means 1 through a central opening 28 and a pairof circumferentially spaced openings 29 in the annular nut 10. Theopenings 29 not only serve as communication means between the outerchamber 27 and the exterior of the unloading valve, but are also adaptedto be engaged by a conventional pin wrench, not shown, whereby rotationmay be imparted to the annular member 10 for moving the same axiallywithin the tubular housing element 7.

As shown in FIG. 1, the upper or outer end of the bypass valve stem 23is diametrically reduced to be received in a central opening of thepiston 25. The piston 25 is clamped between the stem 23 and an axialretainer post 30 having a reduced diameter threaded inner end 31 that isscrew threaded into a similarly threaded axial opening in the outer endof the stem 23. The screw threaded end 31 cooperates with the upperportion of the post 30 to define an annular shoulder 32 that engages theupper surface of the piston 25 to securely clamp the piston 25 betweenthe post 30 and an annular shoulder 33 on the stem 23. As shown, thepost 30 is loosely received within the opening 28, and at its upper endis provided with a screw driver slot 34 so that the post 30 may beconveniently tightened against the piston 25.

Means for yieldingly urging the piston 25 in a direction to move thebypass valve 22 into seating engagement with the valve seat formed bythe annular member 9 comprises a plurality of resilient conical washerscommonly known as "Belleville" springs 35. The springs 35 are mounted onthe post 30 and arranged in axial pairs to provide a stack of saidsprings, the springs of each pair having concave sides in face-to-facerelationship. As shown, the springs or washers 35 are interposed betweenthe piston 25 and the inner surface of the annular nut 10. Bypass valveclosing bias against the piston 25 may be varied by adjusting theannular nut 10 as well as by varying the number of springs or washers 35within the chamber 24. The bypass valve stem 23 is formed to provide anannular groove in which is mounted a sealing ring in the nature of aconventional O-ring 36. An annular flange 37 is mounted on the stem 23adjacent the bypass valve element 22 and supports a Belleville spring 38that is adapted to engage the adjacent end of the bushing 8 to cushionthe valve opening movement of the bypass valve element 22.

At its inner end, the tubular housing element 7 is formed to provide aplurality of circumferentially spaced arcuate feet 39 that engage thebushing 8 and hold it in position in the housing member 2. A third fluidpassageway 40 extends from the axially inner end of the chamber portion26 to the first fluid passageway 13 between the check valve 15 and theoutlet port 12. Preferably, and as shown, the tubular housing element 7,bushing 8, annular valve seat member 9, and piston 25, are all providedwith sealing elements in the nature of commercially available O-rings toprevent leakage therebetween and adjacent portions of the valvestructure.

In use, it may be assumed that the inlet port 11 is connected to asource of fluid under predetermined pressure such as a constant deliverypump, that the outlet port 12 is connected to a conduit, not shown, butleading to a delivery valve, not shown, and that the bypass port 20 isconnected to a conduit, not shown, but leading to the source of fluid.When the delivery valve connected to the outlet 12 is open and liquid isbeing delivered to the inlet port 11, liquid forces the check valve 15open and flows outwardly through the openings 18 to the delivery valve.The washers or springs 35 are so arranged that they will maintain thebypass valve 22 in a closed position when fluid pressure within thepassageway 13 remains below a predetermined maximum pressure. When thedelivery valve, not shown, is closed, pressure builds up in thepassageways 13 and 40 and chamber portion 26 to move the piston 25 andbypass valve in a direction to open the bypass valve element 22, againstbias of the Belleville springs 35. Fluid then flows outwardly throughthe bypass passageway 21 and port 20 back to the source of supply of thefluid until the delivery valve 12 is opened to relieve pressure withinthe passageway 13.

I have found that the conical spring washers may be advantageously used,not only because they may be easily removed or added or otherwisearranged to provide varying bias, but that the spring rate and theaction of the conical spring washers makes for smooth and even operatingmovement of the bypass valve element 22, and keeping valve bounce to aminimum. Coil compress on springs may be substituted for the springwashers 35, if desired, but I have found that smoother action is gainedwith the spring washers 35. The above described arrangement makes for acompact unit which avoids the ungainly appearance found in the usualunloader valves having exterior springs.

While I have shown and described a commercial embodiment of my unloadervalve, it will be understood that the same is capable of modificationwithout departure from the spirit and scope of the invention, as definedin the claims.

What is claimed is:
 1. An unloader valve comprising:a. valve housingmeans having aligned inlet and outlet ports and defining astraight-through first passageway connecting said ports; b. a one-wayoutlet check valve in said first passageway adjacent said outlet port;c. said housing means further defining, a bypass port, a secondpassageway connecting said bypass port with said first passageway, avalve seat at one end of said second passageway and at one side of saidfirst passageway, and a cylindrical chamber axially aligned with saidvalve seat; d. a piston in said chamber dividing the chamber into aninner pressure chamber portion and an outer chamber portion open to theexterior of said housing means; e. said housing means further defining,an opening between said pressure chamber portion and said firstpassageway, and a third passageway communicating at one end with saidfirst passageway between said outlet port and said check valve and atits other end with said pressure chamber portion; f. a bypass vlaveelement disposed in said first passageway and having a stem extendingthrough said opening and connected to said piston, said bypass valveelement being movable with said piston toward and away from valveclosing engagement with said valve seat; g. yielding means in said outerchamber portion yieldingly urging said pistong and said bypass valveelement in a valve closing direction, said yielding means comprising aplurality of resilient conical washers arranged in axial pairs toprovide a stack of said washers, the washers of each pair having concavesides in face-to-face relationship; and h. a conical washer mounted onsaid bypass valve element stem and positioned to engage said housingmeans to cushion said bypass valve element during opening movementthereof.
 2. The unloader valve defined in claim 1 characterized by aretainer post extending axially from said piston within said outerchamber portion, said post having an inner end portion secured to saidbypass valve element and having an annular shouler engaging said piston,said conical washers being mounted on said post.
 3. The unloader valvedefined in claim 2 in which said housing means includes an adjustmentplate in said outer chamber adjustably movable toward and away from saidpiston, said conical washers being interposed between said adjustmentplate and said piston.